0049-2702-XXX Alliance Series Modems – USER MANUAL
08/05/2010
Rev. A
Page 155 of 197
•
SIZE
Shows size of data packets (MNP) or blocks (V.42/V.42bis) currently being
transmitted. MNP uses “shorter” packets to transmit through noisy lines and “longer”
packets (which allow greater throughput) when line conditions are good. The maximum
MNP packet size is 256 characters (MNP classes 4 and 5) or 64 (MNP classes 1-3). The
block size for V.42/V.42bis is fixed at 128 characters.
•
Transmitted (TX)
Number of packets or blocks transmitted since the connection was
established (or since counter reset).
•
Errors (ER)
Number of retransmissions (retransmitted because of data errors) since the
connection was established (or since counter reset). (
Note
: Some errors are “normal”
when flow control is used.)
To reset the TX and ER counters, press button 2 while the packet screen is displayed. These
counters reset automatically when a dial call disconnects, but in leased line modes (including
dial backup auto-recovery), they reset only if you press pushbutton 2 with the packet screen
displayed or reset the modem by selecting RESET.
Mode and Rate Screen
This screen shows the following data:
•
MODE
Below
MODE
, this screen indicates the error correction status:
Display
Error correction status
NORMAL
Error correction and buffer mode are both
inactive.
V42
V.42 error correction (LAPM) is active.
V42bis
V.42bis error correction (LAPM with data
compression) is active.
MNP 01 – MNP 05
MNP error correction is active.
BUFFER
Buffer mode is active.
OFFLINE
Modem is off-line.
•
RATE
This screen shows the data rate of the DTE.
RATE CHANGE SCREEN
In V.34 or V.32bis mode, if the Rate Renegotiation Procedure (RRP) option is enabled, the
modem will automatically adjust during data transmission to a higher or lower data rate,
depending on the receive signal quality. For diagnostic purposes, the RATE screen (accessed
from screen 3 of the MAIN MENU) may be used to
manually
initiate speed renegotiation from
the front panel.